The rhizosphere, a narrow zone of interaction between plant roots and soil, represents a critical interface regulating plant growth, nutrient cycling and soil health. This study reviews the ecological and functional significance of plant-microbe interactions within the rhizosphere and their implications for sustainable agriculture. Root exudates, microbial diversity and soil physicochemical properties collectively shape the composition and activity of microbial communities. Beneficial organisms, including plant growth-promoting rhizobacteria (PGPR) and mycorrhizal fungi, facilitate nutrient mobilization, enhance stress tolerance and suppress soil-borne pathogens. Conversely, pathogenic microbes such as Fusarium and Ralstonia negatively impact crop productivity and threaten agricultural sustainability. Emerging biotechnological approaches harness these beneficial interactions to improve soil fertility and reduce dependence on chemical fertilizers and pesticides. Techniques such as microbial inoculants, rhizosphere microbiome engineering and biocontrol agents show promise for enhancing crop performance under sustainable farming systems. However, their efficiency is often limited by variable microbial colonization, inconsistent field responses and environmental heterogeneity. Recent advancements in molecular tools, including metagenomics and the development of synthetic microbial communities, provide new insights into rhizosphere complexity and functionality. Understanding and managing these interactions can drive the development of ecologically sound strategies to enhance crop productivity, promote soil resilience and address global challenges of food security and climate change. 
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Plant-Microbe Interactions and Rhizosphere Dynamics for Sustainable Agriculture: A Review

<div>Background:&nbsp;Acinetobacter&nbsp;is an aerobic gram negative, non-spore forming, oxidase negative, catalase positive, non-motile encapsulated coccobacilli. They are ubiquitous in nature mostly isolated from soil, water, food, sewage, animal and human skin, marine water and rhizosphere of maize and wheat. The present study was focused on isolation and characterization of a native strain of rhizospheric&nbsp;Acinetobacter&nbsp;for plant growth promoting ability through different microbiological and morphometric parameters under greenhouse conditions. 
 
Methods:&nbsp;Rhizosphere soil samples were collected from maize fields and processed as per the standard microbiological procedure. The morphology was reconfirmed through scanning electron microscopy. DNA extraction was performed by using al. Two sets of primers (universal and specific for&nbsp;H. pylori) were used to amplify the&nbsp;16S ribosomal&nbsp;gene. Sanger sequencing was applied and the resulted sequences were matched with the sequences of the National Center for Biotechnology Information (NCBI) nucleotide database. The evolutionary aspects were analyzed using MEGA7 software. 
 
Result:&nbsp;The strain exhibited plant growth promoting attributes of ammonia generation, inorganic and organic phosphate solubilization 1-aminocyclopropane-1-carboxylate deaminase activity. The strain was identified as&nbsp;Acinetobacter&nbsp;pittii&nbsp;through 16S rRNA sequencing and was designated as Acinetobacter pittii strain F2 5 with the accession number KM677194. Scanning electron microscopy was carried out to reconfirm the morphology of the strain. Under laboratory and green house conditions the strain improved the shoot and root length and its biomass of the treated maize seedlings as compared to the uninoculated control underscoring the plant growth potential of these strains in sustainable agricultural practices.</div>

Plant Growth Ameliorating and Rhizosphere Competent Native Acinetobacter pittii Strain F2 5 from the Rhizosphere of Zea mays L.

The study was conducted in above 50 year old tea plantation in Naharoni, Golaghat district of Assam with the objective to know soil physicochemical properties under long term tea monocropping. A total of 48 soil samples were collected from the rhizosphere zone of tea bush in four seasons namely pre-monsoon, monsoon, post-monsoon and winter from three depths i.e.0-20, 20-40 and 40-60 cm. Soil profile study was also done in non-rhizosphere zone. Soil pH ranged from 4.1 to 4.8 in rhizosphere soils and 4.5 to 5.1 in soil profile. Soils are strongly acidic in reaction. Studied soils were rich in soil organic carbon. In 0-20 cm soil depth of rhizosphere soils organic carbon ranged from 1.32 per cent in monsoon season to 1.82 per cent being highest in winter season. And in subsurface soils it ranged from 0.79-1.25 per cent in 20-40 cm to 0.66-0.78 per cent in 40-60 cm soil depth. In soil profile study it varied between 1.71-0.20 per cent. Irrespective of any season significantly higher concentration of nutrient elements such as N, P and K were recorded in top layer (0-20 cm) of soil. Nutrient elements showed significant seasonal variations. Moderate quantity of available nitrogen was found in all the three depths in rhizosphere soils. Low to medium amount of available nitrogen was recorded in the soil profile of non-rhizosphere soils. Available Phosphorous was recorded high and it ranged between 64.22-71.35 kg ha-1 P2O5 in 0-20 cm soil depth and decreased significantly in the subsurface soils. Medium range of available potassium 185.56-232.68 kg ha-1 K2O was recorded in top soils and it was very low in 20-40 and 40-60 cm soil depth. Cations like exchangeable Ca and Mg were also found in low amount and did not show significant seasonal variation. From the results it can be concluded that the soils are poor to moderate in concentration and availability of major soil nutrients and also there is imbalance in their availability with soil depths and seasons.

Soil nutrient dynamics in tea agroforestry ecosystem of&nbsp;Golaghat district of Assam

<div style="text-align: justify;">Background: The occupation of soil by plants is known to induce changes in the soil chemical and physical properties by shoot decomposition and root growth and secretion.&nbsp; Methods: In this study we investigate the degree to which the total and the phytate mineralising rhizospheric communities bacteria are affected by the growth of six Recombinant Inbred Lines (RILs) of common bean (Phaseolus vulgaris). The six RILs tested were contrasted on adaptation to P (phosphorus)-deficiency from sensitive to tolerant. Rhizosphere samples were taken three times during the plant developmental stage and the changes in the density and the phytase activity of those communities relative to the P content were studied. Bacterial community was followed by culturing and measuring total community DNA of soil to allow a cultivation- independent analysis, by amplification of the 16S rRNA gene using real time PCR. Result: Our results showed that successional moves in the rhizosphere bacterial density as plant mature confirmed that plants select their own rhizosphere community. Moves of the bacterial community in the rhizosphere were more pronounced in mature common bean and phytase enzymatic activity confirmed the ability of this plant to mobilise a functional bacterial community when the bean needs high quantities of phosphorus. This study demonstrates that common bean selects a microbial community and its density change in response to plant growth.</div>

<div style="text-align: justify;">Do Phaseolus vulgaris Development Stages Influence the Total Rhizospheric Bacterial and the Phytate Utilising Community?</div>

<div>Microbes are associated inside and outside tissue parts of producers like plants, lichen, algae and phototrophic bacteria. Biofertilizer bacteria, fungi, algae and protozoa provide the suitable environment condition, nutrition constituents and inhibit harmful microorganism from rhizosphere zone. Biofertilizer and biocontrol microbes play key roles for improved soil texture, secreting, hormones, antibiotics and various stress signal compounds, enhancement plant parts elongation and prevent pathogen microbial population. Plant growth promotion rhizosphere microorganisms can improve crop tolerance for the non- living stresses such as drought, heat and salinity and living stress such as soil borne pathogens, over load of the microbial population liable to turn out to be more incessant as various atmosphere design keep on creating. Plant disease major issue for loss of productivity and unsafe for living organism due to chemical pesticides, insecticides, fungicides, bactericides and chemical fertilizer. Due to its high potential as an alternative/complement to these pesticides, biological disease control is now generally recognized and constitutes a low cost-efficient eco-friendly biofertilizer, biocontrol, biopesticide and bioinsecticide.</div>

Promoting Rhizosphere Microorganisms and Biopesticides: A Review

<div>Background: The present study on the topic &ldquo;Phytomorphology and nutrient dynamics of mulberry leaves&rdquo; revealed high variability among mulberry varieties. Internodes were largest in variety Tr4 (6.06%). Actual leaf area was high in variety S146 (275.57 cm2). Numbers of leaves per meter branch was largest in variety S1531 (20.9). During 5 periodic sampling from sprouting to maturity average fresh and dry leaf weight of 100 leaves was high (197.93g) and (60.24g) respectively during 5th sampling. Average moisture content was high (83.41%) during 1st sampling highest average chlorophyll content (SPAD value) was also observed during 4th sampling (40.01%). Acidity was also high in variety Tr4 during maturity. Sugar content was high in variety T1 (3.66%) during 1st sampling (15 days). Starch and ash content was high in variety S1708 (43.06%) and (32.50%) during 5th sampling. Nitrogen and protein content was highest in variety S1608 (5.02%) and (31.56%) respectively during 1st sampling.&nbsp; 
 
Methods: In the field-laboratory investigation was conducted at Division of Sericulture,&nbsp;Division of Biochemistry and Plant Physiology, SKUAST-J, Chatha, during spring 2013. Ten mulberry varieties T1, Tr4, V1, S146, S1708, S799, S1608, S1531, S41 and Sujanpur were evaluated for phytomorphological and nutrient dynamic studies. The experiment was laid in complete randomized block design with three replicates. Each variety was taken as treatment and observations were recorded after 15 days interval upto 75th day after sprouting.&nbsp; 
 
Result: On the basis of current result, parameter observed fluctuations from the date of sprouting till maturity. Varietal response to periodic sampling too varied. Protein decreases age along with sugar, nitrogen. On the contrary starch, biomass, ash, chlorophyll shown a gradual increase. This information can be utilized to harvest a particular type of leaf for a particular age and rearing.</div>

<div>Phytomorphology and Nutrient Dynamics of Mulberry Leaf</div>

<div>Background: Anestrus is one of the most commonly encountered infertility problems in cattle and buffalo in India. Jaffarabadi is one of the heaviest buffalo breeds of the world and is a native of Saurashtra region of Gujarat. The breed is known for poor reproductive efficiency. To improve its reproductive efficiency, this study was undertaken on acyclic Jaffarabadi animals employing double Ovsynch protocol and its assessment through ovarian dynamics and blood biochemical and endocrine profile on a farm.&nbsp; 
 
Methods: The study included acyclic post-pubertal Jaffarabadi heifers (age 42&plusmn;2 and 48&plusmn;2 months; Gr-I and Gr-II, n=6 each) and the postpartum lactating acyclic buffaloes (Gr-III, n=6) using a double Ovsynch protocol, which consisted of i/m injections of 20 &micro;g Buserelin acetate on days 0, 10, 17 and 26 and 500 &micro;g Cloprostenol sodium on days 7 and 24, with a timed insemination on day 27. Ovarian dynamics was monitored by performing ultrasonography using real-time B-mode ultrasound scanner together with blood sampling for hormonal and biochemical profile on each day of hormone therapy and then on days 0, 12, 21 and 35 post-AI. The animals inseminated at induced estrus/FTAI were followed for return to estrus, if any. Pregnancy was confirmed in non-return cases on day 35 by ultrasonography and on day 70 by per rectal examination. The findings on ovarian dynamics, plasma endocrine and biochemical profile were compared statistically between groups and periods and fertility rates between groups. 
 
Result: In animals of treatment group I and II, a significant (p&lt;0.05) increase in numbers of small follicles was observed on day 26. Number of large sized follicles was significantly (p&lt;0.05) higher on day 26 in comparison to day 0 and day 7 in group III animals. Large and subordinate follicular diameters increased gradually, but the differences between periods were significant (p&lt;0.001) only in group III with the highest diameter of large follicle on day 17. Plasma FSH and LH concentrations differed significantly (p&lt;0.001) among groups at all-time intervals. Plasma LH in group I and III differed significantly (p&lt;0.001). Plasma estrogen level was significantly (p&lt;0.05) higher in group II than group III. Plasma progesterone concentrations in group I and II animals were significantly higher on day 35 post-AI. Plasma insulin levels were significantly (p&lt;0.01) lower on all days for group III animals than group I and II. Blood glucose level was significantly (p&lt;0.001) higher in group I on day 17 as compared to group II and III. Plasma total cholesterol was significantly (p&lt;0.05) higher in group III as compared to group I and II. The conception rates at first service/FTAI in double Ovsynch treated animals of group I, II and III were 66.66, 83.33 and 16.66 %, respectively. Thus it was concluded that ovarian structures and the plasma endocrine profile reflected the ovarian response to different hormonal injections and that double Ovsynch protocol could be a better choice for improving conception rate in post-pubertal acyclic Jaffarabadi buffalo heifers as compared to multiparous acyclic buffaloes.</div>

Evaluation of Double Ovsynch Protocol in Acyclic Jaffarabadi Heifers and Buffaloes with Respect to Ovarian Dynamics, Hormonal Profile and Fertility

Clusterbean [Cyamopsis tetragonoloba (L.) Taub.] is an important commercially utilizable crop grown in arid zone of India. Microorganisms present in the rhizosphere of this crop produce various plant growth-promoting substances and enhance the availability of nutrients to the plants. Therefore, fifty five bacterial isolates obtained from the rhizosphere of clusterbean were explored for beneficial characteristics. Twenty rhizobacterial isolates produced indole acetic acid ranging from 3.9 to 24.7 &micro;g/mL. Only six isolates HCS7, HCS19, HFS7, HFS9, HFS10 and HFS12 showed d-aminolevulinic acid production varying from 1.3 to 7.0 &micro;g/mL. Fourteen isolates showed solubilization of potassium on mica containing Aleksandrov medium plates. Stimulation of root and shoot growth of clusterbean seedlings on water agar plates was observed by inoculation of eleven rhizobacterial isolates at 5 and 10 days of growth whereas some isolates showed stunting effect on the growth of shoot and root as compared to uninoculated seedlings. At 60 days of plant growth, inoculation of Bradyrhizobium strain GSA11 and Rhizobium strain GSA110 showed significant nodulation and their inoculation resulted in 141.94 and 151.43% gains in shoot dry weight, respectively under chillum jar conditions. Coinoculation of Bacillus isolate HCS43 with Rhizobium strain GSA110 formed 48 nodules/plant and plant dry weight was enhanced by 190.09% in comparison to uninoculated control plants.&nbsp;

Growth stimulation of clusterbean (Cyamopsis tetragonoloba) by&nbsp;coinoculation with rhizosphere bacteria and Rhizobium&nbsp;

<div>Background: Understanding of ovarian follicular dynamics and endocrine regulation is essential to design and use interventions to optimize reproductive efficiency. Bos indicus and Bos taurus cows have some differences in their follicular dynamics and ovarian steroidal hormones. The present study was planned to understand follicular dynamics vis-a-vis ovarian steroids profiles in Sahiwal cattle. 
 
Methods: The study was conducted in normal cyclic, pluriparous, non-lactating Sahiwal cows (n=7). Trans-rectal ultrasonography was performed to record the location, size, number of follicles and size of corpus luteum (CL) from the beginning, till the end of experiment. The dataset was used to characterize the follicular wave emergence, growth, regression, time of selection and ovulation of the dominant follicle in each cow.&nbsp; 
 
Result: Three Sahiwal cows showed two wave and four cows showed three wave estrous cycles with mean interovulatory length of 20.33&plusmn;0.33 and 22.50&plusmn;0.28 days, respectively. No significant difference was recorded in the maximum diameter of corpus luteum, P4 and E2 plasma levels between 2-wave and 3-wave estrous cycles. The peak progesterone values of 6.00&plusmn;0.91 and 6.2&plusmn;1.2 ng/ml and peak estradiol values of 15.83&plusmn;0.60 and 14.31&plusmn;0.44 ng/ml were recorded in 2-wave and 3-wave estrous cycle, respectively. The results showed that Sahiwal cows had 2-wave and 3-wave estrous cycle and the 3-wave estrous cycle had comparatively longer inter-ovulatory period and smaller maximum diameter of second wave dominant follicle than 2-wave estrous cycle.</div>

Studies on Ovarian Follicular Dynamics and Steroid Profiles in Sahiwal Cattle

Background: Lentil plants enhance soil quality and productivity by forming symbiotic relationships with a diverse group of microbes present in the rhizosphere. The Cultivar-specific interactions, Rhizobium strains and plant genetics influence microbial diversity in the rhizosphere. This study aims to evaluate and compare bacterial diversity in lentil rhizospheres using metagenomics and 16S rRNA gene sequencing. 
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Methods: Rhizosphere soil samples from lentil cultivated sites were used for sequencing analysis. Genomic DNA was isolated from the rhizospheric soil using a standard protocol. Sanger/Illumina sequencing with a read length of 1.9 was performed on the extracted genomic DNA. Kraken 2 was used for taxonomic classification. Alpha diversity was measured in metagenomic samples to assess diversity. 
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Result: The present research study identifies Proteobacteria as the dominant phylum and the important taxon Rhizobium leguminosarum in the lentil rhizosphere microbiome. At the class level, Gammaproteobacteria were the most dominant (64.23%), followed by Alphaproteobacteria (4.633%), Betaproteobacteria (2.042%), Deltaproteobacteria (1.691%), Epsilonproteobacteria (0.2565%), Actinobacteria (5.376%) and Rubrobacteria (0.2303%). Further studies will focus on metabolic pathways, nutrient cycle, stress tolerance and pathogen suppression. These microbial communities could improve crop quality and sustainability in a fluctuating climate. 
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Plant-Microbe Interactions and Rhizosphere Dynamics for Sustainable Agriculture: A Review

Plant Growth Ameliorating and Rhizosphere Competent Native Acinetobacter pittii Strain F2 5 from the Rhizosphere of Zea mays L.

Soil nutrient dynamics in tea agroforestry ecosystem of Golaghat district of Assam

Do Phaseolus vulgaris Development Stages Influence the Total Rhizospheric Bacterial and the Phytate Utilising Community?

Promoting Rhizosphere Microorganisms and Biopesticides: A Review

Phytomorphology and Nutrient Dynamics of Mulberry Leaf

Evaluation of Double Ovsynch Protocol in Acyclic Jaffarabadi Heifers and Buffaloes with Respect to Ovarian Dynamics, Hormonal Profile and Fertility

Growth stimulation of clusterbean (Cyamopsis tetragonoloba) by coinoculation with rhizosphere bacteria and Rhizobium

Studies on Ovarian Follicular Dynamics and Steroid Profiles in Sahiwal Cattle

16S Metagenomic Analysis of Microbial Diversity from the Rhizosphere of Lentil (Lens culinaris Medik) Collected from Tezpur, Assam